A versatile method for assessing pathogenicity of Hymenoscyphus fraxineus isolates to ash foliage

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We present a new method of inoculating Fraxinus excelsior (ash) rachises with Hymenoscyphus fraxineus (Hf) which is more rapid that previous inoculation methods and allows foliar symptoms to be readily assessed.  We use 10 ash seedling trees inoculated with five isolates of Hf to develop a five-point progress scale of symptom development from no lesion (0), lesion on rachis (1), ‘pre-top dead’with curling of distal leaflets and bending of the rachis (2), top dead, with wilting and death of distal leaflets (4) to leaf abscission (4).  We show that differences in host resistance can be rapidly assessed using this method.